A stent is a generally tubular device that is used to support a bodily lumen.
A stent is typically delivered to a desired bodily location via a catheter. In the case of a mechanically expandable stent such as a balloon expandable stent, the stent is disposed about the balloon and crimped to the balloon to prevent undesired movement of the stent relative to the balloon.
A number of techniques for crimping a stent to a balloon are used. One such technique that is commonly used in the radiological suite involves hand crimping the stent to the balloon. A stent is placed over an uninflated balloon and then squeezed with the fingers until the stent is in intimate contact with the uninflated balloon. The technique is highly operator dependent and can affect stent profile and stent placement with respect to the balloon and radiopaque markers. It can also affect the dilatation length of the stent and lead to pinching of the balloon.
Other techniques for crimping stents involve the use of mechanical devices for crimping stents. Mechanical stent crimpers have been disclosed in a number of patents including U.S. Pat. No. 6,108,886, U.S. Pat. No. 6,092,273, U.S. Pat. No. 6,082,990, U.S. Pat. No. 6,074,381, U.S. Pat. No. 6,063,102 and U.S. Pat. No. 5,992,000. Mechanical stent crimpers have also been disclosed in a number of copending, commonly assigned patent applications including U.S. application Ser. Nos. 09/401467, 09/401213, 09/404986 and 09/401218.
Typically, mechanical stent crimping devices are either used to crimp the stent to the catheter prior to shipping the stent or in the radiological suite. In the latter case, the radiologist selects a bare stent with the desired properties and then mechanically crimps the stent to the desired balloon catheter.
There remains a need for novel stent crimping devices that are capable of uniformly crimping a stent to a catheter and that may be employed at the point of use of the stent. There is also a need for stent crimping devices that may double as a shipping container for protecting the stent during shipping.
All U.S. patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
The invention in various of its embodiment is summarized below. Additional details of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
The abstract provided herewith is intended to comply with 37 CFR 1.72 and is not intended be used in determining the scope of the claimed invention.
The invention is directed to a stent container comprising a first wall at the proximal end of the container and a second wall at the distal end of the container. An opening is provided through the first wall. The opening, sized for receiving an uncrimped stent therethrough, opens into a chamber. The chamber is reducible in size from a first enlarged size to a second reduced size. In the first enlarged size, the chamber is sized for receiving an uncrimped stent therein. A plurality of bars extending from the first wall to the second wall, in conjunction with the first and second walls, define the chamber. The bars are movable between a first position and a second position. In the first position, the plurality of bars and the first and second walls define the periphery of the chamber in the enlarged size. In the second position, the plurality of bars and the first and second walls define the periphery of the chamber in the reduced size.
In one embodiment, the bars are movably received in the first and second walls. The first wall has a center and a plurality of slots disposed about the center. Each of the slots arcs toward the center with the bars movably received in the slots. The second wall has a plurality of radially disposed grooves therein, with the bars movably received in the grooves. The first wall is optionally rotatable relative to the second wall to move the bars from the first position to the second position and vice versa. The first and second walls may also be constructed such that the bars slide in a purely radially inward direction.
In another embodiment, the bars are flexible. The bars, disposed in the first and second walls and fixed to prevent radial movement, are capable of being flexed between the first and second positions to reduce a stent in size. The bars may optionally be rotatable.
The bars of the stent containers disclosed above are desirably spaced apart such that the stent is visible between adjacent bars to facilitate positioning the stent and any balloon to which the stent will be crimped therein. The bars may also be made of a transparent or translucent material to facilitate positioning.
The container may optionally have an uncrimped stent therein. The uncrimped stent may be reduced in size immediately upon insertion into the container, after one to two hours, one to two weeks, one to two months, six months or longer or any other suitable period of time.
The inventive container is constructed and arranged such that the chamber in the second reduced size is smaller than the uncrimped stent.
The invention is also directed to containers such as those described above where the chamber comprises a stent which has been reduced in size and optionally, crimped to a catheter.
The invention is also directed to a method of reducing a stent in size. In accordance with the method, a stent is-provided in a container. The container has a first end wall and a second end wall and a plurality of bars extending between the first end wall and the second end wall. The first and second end walls and plurality of bars define a chamber in which the stent is received. The bars are movable between a first position in which they do not contact the stent to a second position in which they contact the stent and provide an inward force to the stent. The bars are in the first position when the stent is placed in the container. The bars may be moved from the first position to the second position thereby reducing the stent in size. Optionally, a medical balloon may be disposed within the stent prior to moving the bars and the stent crimped to the balloon. The stent may be reduced in size immediately upon insertion into the container or after a period of time such as at least one day, week, month, a half year or even years.
The invention is also directed to a method of reducing a stent in size using a coil. In accordance with the invention, a coil is disposed about a stent. The coil has a first end and a second end. The coil is reduced in diameter by moving at least one of the first and second ends of the coil relative to the other end so that the coil contacts the stent and applies an inward force to the stent sufficient to reduce the stent in size. The coil may be made of a suitable material such as a metal or polymer. Further in accordance with the method, a medical balloon catheter having a medical balloon portion may be provided. The stent may be disposed about the balloon portion of the medical balloon catheter prior to reduction of the stent in size. The coil may then be used to crimp the stent to the balloon.
In all embodiments of the invention where the stent is loaded onto a balloon, optionally a centering pin may be provided to guide the stent onto the balloon.